I would like to allocate a bank transaction which I have already downloaded to some supplier invoices and customer invoices.

Hi there, @njdarling87.

You can match the downloaded transactions with the one you already entered. This links the two to avoid duplicates.

Here's how:

1. Click Banking, then choose Banking.
2. Go to the For Review tab.
3. Look for the deposit, then click to open the transaction.
4. Review the Records found. These transactions are ones you already entered in QuickBooks.
5. Click the link next to each record to get more details.
6. Review the Deposit to field on the forms. 
7. Tap Match.

To know more about matching transactions in QuickBooks, click this article: Add and match downloaded bank transactions [Video].

I'm also linking an article that will help you in the future: Reconcile a bank account and common troubleshooting tips [Video].

Let me know if you have any follow-ups or other questions. I'm here to help. Take care.

I am trying to do this but it is not bringing up the credit to match

Hi there! I'll assist you in handling the transaction in question, njdarling87.

If a transaction you put into QuickBooks isn't showing up, make sure it hasn't been reconciled yet, that you're using the same bank account as intended, that it hasn't been matched to another bank-downloaded transaction previously, and that it doesn't fall outside of the shown date range.

Moreover, review and categorize the downloaded transactions before adding them if you haven't already manually entered transactions. Take these actions:

1. Go to the Banking menu.
2. ​Under the For Review tab, select the transaction row to review the type of transaction.
3. Choose a category from the Category dropdown button
4. If you have VAT turned on, select the VAT amount from the VAT dropdown.
5. Click Add to move the transaction from the Categorised tab to the In QuickBooks tab.

For more details, read this article: Add and match downloaded bank transactions [Video].

You can also unmatch downloaded bank transactions or move them to another account.

Please touch base with me here if you need further assistance with your transactions. The Community space is always around to provide instructions. Keep safe.